Helium Bluetooth speakers powered by supercapacitors

Sharing music with friends through laptop or smartphone speakers can be less than satisfying, which perhaps goes some way to explaining the overwhelming choice of portable Bluetooth speakers that come into view as you enter a consumer electronics store. Such offerings all suffer the same problem, though. Just as you're getting your groove on, the built-in battery dies and you have to wait hours while it juices up from a wall socket. What mobile music lovers like me need are wireless speakers that can charge in minutes, and then last for hours. An impossible dream? Sam Beck from Portland's Blueshift doesn't think so. He's developed mono and stereo portable Bluetooth speakers powered by supercapacitors. Helium users can look forward to a super quick charge time, hours of full volume playback and years of recharge cycles before needing to consider a supercap refresh.

The 12 x 7 x 4 in (31 x 18 x 10 cm) Helium Mono packs four Maxwell BCAP0350 supercapacitors, each about the same size as a D-cell battery, and a single 4-inch Fostex FE126E full-range driver in a hand-made ported bamboo cabinet tuned to 105 Hz. The Helium Stereo unit doubles the number of supercaps and speakers and measures 18 x 9 x 6 in (46 x 23 x 15 cm). The speakers, which can be fronted by removable grilles if desired, are driven by a Class-D amplifier, and are capable of handling all audio frequencies, though there may not be enough low end for some tastes. Beck tells us that the "bass is not thumpy or bone rattling, but it's there – I listen to a lot of Young Jeezy and this handles it great."

Wireless streaming from smartphones, tablets or suitably-capable computers and laptops is possible thanks to integrated Bluetooth 2.1 with A2DP, and AAC and Apt-X codecs. Helium users can expect a good 6 hours of full volume playback before the juice runs out, but it's reported to take only 5 minutes to charge up the supercapacitors, so by the time the drinks are mixed and served, the party is ready to resume. Music can also be fed directly into the Helium speakers via a 3.5 mm audio input port.

The Blueshift project is open source, meaning that the company will freely share plans and schematics so that tinkerers can build their own speakers, or modify the design to suit personal needs or tastes.

With many battery-powered wireless speakers available at the moment, users cannot open up the portable box and refresh the cells when they start to reach the end of their useful lives. The Blueshift speakers are built with longevity in mind, and users can swap out supercaps when they start to show signs of age, though it could be a long while before such things are necessary.

"You could replace the caps, but I don't think you're going to need to," says Beck. "The rated lifetime is 500k cycles/10 years, but at that point they should still have 80 percent of original capacitance, and moreover that's 100 percent of their rated current and max temperature. This application really isn't that demanding, they should last a really long time. I've been saying 20 years, but I expect more."

Blueshift has launched a crowdfunding campaign on the Portland-based CrowdSupply platform to get its speakers into the hands of portable music lovers. For a pledge of US$180, backers will be supplied with all of the bits and pieces needed to make a supercapacitor-powered wireless speaker, but makers will have to supply their own speaker driver and build their own cabinet.

The first 25 fully-assembled Helium units are going to be built mostly in-house, but these have already been snapped up. The next level represents the first speakers that will be built by contractors. A single-speaker edition is pitched at $400, with the stereo model coming in at $150 more.

If all goes as planned, the first Blueshift speakers should start shipping in February 2014. "After the campaign succeeds, CrowdSupply will keep selling as a regular ecommerce site, plus I'll sell direct through my site," says Beck. "Pricing will be around $450 for mono and $600 for stereo."

If the funding goal is not reached by December 19, however, backers will not be charged and Blueshift will look at other ways to get the speakers out to those who want them.

While Paul is loath to reveal his age, he will admit to cutting his IT teeth on a TRS-80 (although he won't say which version). An obsessive fascination with computer technology blossomed from hobby into career before the desire for sunnier climes saw him wave a fond farewell to his native Blighty in favor of Bordeaux, France. He's now a dedicated newshound pursuing the latest bleeding edge tech for Gizmag. All articles by Paul Ridden

Bass is seriously over-rated. My major annoyance is also the battery, but from the other direction. Why doesn't somebody make a danged bluetooth speaker that uses a standard power supply? Not everybody wants to use these things outside of their home! All I want is something that sounds as good as a $75 boombox, packaged with a bluetooth dongle that I can use with my PC.

Purple-Stater 27th November, 2013 @ 11:12 pm PST

I guess if you are that crazy about having a short recharge time. Don't get me wrong, I do like the idea of using super caps for storage.

It is a novel application, but you pay for it so a hard sell when competing with sub-200 dollar units.

Possible alternative. Hot swap battery units. Charge one, while the other powers the unit. A smaller super cap inside powers the unit for a minute while you swap out the batteries for continuous play. Batteries come with an AC or USB docking station that can charge two batteries at a time.

Strictly off grid, how long would you need? I have a small JBL stereo unit good for most of the day. How often would you need to play music for a whole week straight that you could not afford an hour to recharge the battery?

And in saying that, a modest camping solar panel with USB out will likely keep the show running

So I calculate 5.1 kilojoules of energy for those four 350F caps charged to their maximum voltage of 2.7V. 6 hours of playback would at best amount to an average power if used with 100% efficiency of 236mW. Since music is usually rather low duty factor, of order 1/10 of peak power, if done ideally this could produce some moderate near-field sound pressure levels with a moderately efficient speaker, particularly since the bass energy has been wisely restricted to a rather anemic 110 Hz.

I'd definitely try to audition one of these before committing money, as the volume and particularly the bass may be disappointing. If there is no step-up or regulated step-up conversion to provide the probable rail voltage for the amplifier, which is probably a "filterless" class-D part, the maximum rms voltage will be 7.6V for a fully-charged system and falling with use. Overall tolerable for low listening levels I suppose.

Brad Wood 28th November, 2013 @ 08:48 am PST

The main advantage of caps (in addition to fast charge) is that power from caps is super clean. A clean power supply means very clean and clear sound. They use a full range driver so the sound is coherent and natural. Plus they have a class B amp (not class D). But their enclosure seems to be more about style rather than optimal shape: it is tuned for 100 Hz, should have been lower. This is the reason it doesn't have as much bass as it should. A bigger driver would help too. They don't mention how many watts RMS it produces.

I wouldn't call them portable. Lug-able is more like it.

In summary: a great idea, but at $550 just too expensive.

[Ed: Blueshift PDX has confirmed that the Helium speakers each use a TI TPA2013D1 Class-D amplifier]

sidmehta 28th November, 2013 @ 10:49 am PST

I love the idea of super capacitors and want to get some to play around with. @ Brad: I think this MUST have a DC-DC converter because whereas batteries tend to hold the voltage until they're almost dead then taper off quickly, a capacitor voltage falls off continuously throughout the discharge cycle (you already know this I'm sure).

I think this technology has a serious competitor in Li-Po batteries though. I've built a 320 watt RMS stereo (160 X 2) that would bring the noise control officers around in 10 minutes and it will play at full volume for well over an hour with an 11.1 volt, 8.4 Amp-Hr Li-Po. And the battery has G6 chemistry which means it can be fully charged in less than 10 minutes if you have a bench supply that can deliver 59 amps! My 40 amp supply charges it in about 12 minutes. And there are G8 batteries that are even faster than that. And it's only going to get better.

I have one that will deliver 320 amps continously at 12 volts and twice that in a burst and it's about the size of a standard stapler. They were developed for R/C models. If you Google "Li-Po G8" you'll find some stuff on these.

However they're expensive and they won't last nearly as long as capacitors. But I've seen articles on Gizmag where new technologies are being developed to improve the Li-Po's life. So there's a race on.

warren52nz 28th November, 2013 @ 12:13 pm PST

Yes, that is a clever TI part, as it integrates a boost converter and thus allows for ~constant output power until the input voltage falls below a threshold. According to the datasheet, maximum continuous average output power* is 2.7W into 4 ohms, which is with 10% clipping distortion. As mentioned above, real musical material is usually about 1/10 average power, so my SWAG of 236mW is about right.

A full-range driver of that diameter is already getting unpleasantly directional at high frequencies, so a larger one for potentially better bass response with a lower port tuning will only exacerbate this. Better would be a driver of comparable or smaller diameter with more low-distortion excursion, or a two-way system. But on-axis and near-field listening should be o.k. However, it's clear that the maker wants to show a proof-of-concept here, not blaze new trails in the state-of-the-art in small portable loudspeakers.

*"rms power" is a unfortunately common misnomer. Yes to rms voltage or current, but power is peak or continuous average.

Brad Wood 28th November, 2013 @ 12:51 pm PST

Nice.. too bad the speakers aren't protected.

DAs Siegel 29th November, 2013 @ 08:18 am PST

NB: I should have said above, that real musical material is an average power of about 1/10 maximum continuous average power, hence say 1/10 of 2.5W (not clipping quite as badly as 10%) being 250mW.

Yes warren52nz, if batteries could sustain a lot more charge-discharge cycles, such rapid charging times are certainly competitive.